The Dyer Island Nature Reserve Complex is a protected area off the coast of Gansbaai in the Western Cape, South Africa.

The shallow channel between the two islands is popularly known as Shark Alley.

It is named after Samson Dyer, an emigrant from the US to the Cape Colony in 1806, who lived on the island collecting guano, which he sold to mainlanders as fertiliser.

In 1988, the two islands were named individually as Provincial Nature Reserves.

[6][7] There are 26 species of fish found in the surrounding waters, including the endangered Galjoen.